When talking about boiler steel plate, we imply steel materials that are utilized in superheater tube boiler, the main steam pipe and fireroom manufacturing. Good welding performance, particular high temperature strength and alkali resistance, resistance to oxidation and corrosion would be the main performance requirements of boiler steel plate. Commonly used boiler steel plate consists of low carbon steel smelting in open hearth and low carbon steel electrical smelting, carbon content ought to be managed in 0.16%-0.26%. Pearlite heat resistant steels or austenitic heat resistant steels will come into use when manufacturing high stress boiler. Nevertheless, the insider also use common reduced alloy steel to manufacture boiler these days.
Drum boiler utilizing steel and steam pipe utilizing steel are each great steels for manufacturing steel boiler. To be able to function below higher temperature water vapor within the long term with out extreme permanent deformation and rupture, sufficient hear resisting strength, toughness and organization stability will be needed in drum boiler utilizing steel. The steam pipe utilizing steel asks for sufficient high temperature strength, lasting plasticity, oxidation resistance and corrosion resistance, organization stability and good workability. Being as the key elements of boiler, boiler compression needs high safety requirements, along with bearing very high inner stress and internal medium corrosion and erosion, boiler tube in heating surface need to bear external flame or gas erosion, wear and corrosion of dangerous gas, and so forth.
For boiler tube and boiler steel plate, you will find respective unique requirements.
Cold and hot working efficiency particularly the welding performance ought to be good;
Great thermal conductivity. Heating tube is may have a good heat transfer effect and thick wall element may have faster temperature uniformity;
In operating temperature, boiler steel plate ought to have sufficient strength, reasonable powerful toughness and organization as exact same as nature stability. These will make the component wall thickness proper for simple processing that will not affect the heat transfer impact, and make sure long-term safety operation from steel performance;
Good macrostructure and surface quality. As the former, the white spots, visible layered and so on defects are not allowed to seem, the latter is not allowed on the look of existing defects such as crack, heavy leather, fold, scarred and overburden bed separation for the cause that similar defects might turn out to be a component from the brittle fracture accident source;
High stress boiler steel should be top quality steel or unique high quality steel, throughout smelting, except for top quality raw supplies, usually, refining outdoors the furnace and the vacuum degassing along with other technology will probably be needed to make dangerous impurities, such as sulfur, really, tin, antimony, arsenic, etc and gasoline content material towards the minimum degree to make sure the steel purification, in order to avoid brittle fracture accidents.
According to the chemical composition, boiler steel plate, can be divided into two categories: carbon steel and alloy steel. Carbon content of low carbon steel ought to be managed in 0.15%-0.25% so that the needs of each the strength and the welding performance can be satisfied; The carbon content of alloy steel ought to be no more than 0.25% to assure the high temperature strength of steel, oxidation and also the requirements of the welding efficiency.